Problem: spin-rs is unmaintained

[tomtau]

https://rustsec.org/advisories/RUSTSEC-2019-0031.html

currently used in lazy_static and rustls/ring in tx-query

[yihuang]

Change lazy_static to once_cell:

• no spin-rs dependency
• macro-free api
• proposed to std(https://github.com/matklad/rfcs/blob/std-lazy/text/0000-standard-lazy-types.md)